Methods for enabling user equipment to access radio network, network equipments and user equipments

ABSTRACT

The present application discloses a method for enabling a user equipment to access a radio network, a network equipment and a user equipment. A specific embodiment of the method comprises: determining, by a network equipment, whether a predetermined condition is satisfied; and if yes, the method further comprises: transmitting, by the network equipment, information indicating whether a radio network to which the network equipment belongs is isolated, such that the user equipment performs related operations. In the embodiment, the network equipment informs UE of state information about whether the radio network to which network equipments belongs is isolated or not in different ways, so that the isolated network can provide users with reliable local bearer supporting service continuity, thereby meeting communication requirements for public safety and the like.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 15/544,846,which is the National Stage of International Application No.PCT/KR2016/000557, filed Jan. 19, 2016, which claims priority to ChinesePatent Application No. 201510026042.7, filed Jan. 19, 2015, thedisclosures of which are incorporated herein by reference into thepresent disclosure as if fully set forth herein.

BACKGROUND 1. Field

The present application relates to the technical field of radiocommunication, particularly, to the technical field of accessing to aradio network, and especially to a method for enabling a user equipmentto access a radio network, a network equipment and a user equipment.

2. Description of Related Art

With continuous development of communication technologies, modern mobilecommunications tend to increasingly provide users with multimediaservices with high-speed transmission. FIG. 1 illustrates a systemarchitecture diagram of SAE (System Architecture Evolution). As shown inFIG. 1, a UE (User Equipment) 101 is a terminal apparatus for supportinga network protocol. An E-UTRAN (Evolved UMTS Terrestrial Radio AccessNetwork) 102 is a radio access network comprising a base station(eNodeB/Node B) for providing the UE with interfaces to access radionetwork. An MME (Mobility Management Entity) 103 is responsible formanaging mobility contexts, session contexts and security information ofthe UE. An SGW (Serving Gateway) 104 mainly provides a functionality ofuser plane. MME 103 and SGW 104 may be located in the same physicalentity. A PGW (Packet Data Network Gateway) 105 is responsible forbilling, legally interception and etc. PGW 105 and SGW 104 may also belocated in the same physical entity. A PCRF (Policy charging and rulesfunction) 106 provides QoS (Quality of Service) strategies and chargingrules. An SGSN (Serving GPRS Support Node) 108 is a network nodeapparatus for providing data routing in a UMTS (Universal MobileTelecommunications System). An HSS (Home Subscriber Server) 109 is ahome ownership subsystem of UE and is responsible for protecting userequipment information, such as current locations of the user equipment,addresses of the service nodes, user equipment security information andpacket data contexts of the user equipment.

It is known from FIG. 1 that, generally, the user equipment (UE) mayestablish a communication connection with an operator core network(hereinafter, abbreviated to a macro core network to distinguish it froma local core network) through a radio access network to which UEaccesses. However, when the radio access network is an isolated network(i.e., there is no connection between the radio access network and themacro core network), UE accessing to the radio access network cannotcommunicate with the macro core network. Here, there are severalconditions in which the radio access network becomes the isolatednetwork as below: (1) a fixed base station loses a backhaul networkconnection with the core network and cannot be connected with the corenetwork in the isolated state. One or more isolated and fixed basestations may constitute an isolated radio network. (2) For requirementsof communication services with public safety, some nomadic base stationsare deployed temporarily in some areas without macro radio networkcoverage in order to provide the public safety users with public safetyservices. These nomadic base stations generally do not have the backhaulto connect to core network entities of the macro network. One or morenomadic base stations may constitute an isolated radio network. (3) Oneor more isolated and fixed base stations and nomadic base stations mayconstitute an isolated radio network.

When the radio access network is isolated completely or the bandwidthbetween the radio access network and the core network is limited, it isstill desired that safe and reliable services can be at least providedto the public safety UE, thereby supporting implementation with publicsafety tasks. At present, in order to make the isolated radio networkproviding the public safety public safety UE services, a local corenetwork can be enabled for the isolated radio network. Particularly, ifthe fixed or nomadic base stations support functions of local corenetwork, after the base stations become the isolated state, the localcore network can be enabled to serve UE(s), to provide reliable localbearer for UE(s). Alternatively, when an isolated base station detects alocal core network which is allowed to connect, for example, the localcore network enabled by another base station, the isolated base stationcan establish connections with the detected local core network, and thenprovide UE with services. Generally, there is no connection between thelocal core network and the macro core network.

Although the isolated radio access network and the local core networkcan constitute an integral isolated radio network, there are alsoseveral problems in an aspect of enabling the user equipment to accessthe radio network.

SUMMARY

The present application provides a method for enabling a user equipmentto access a radio network, a network equipment and a user equipment toaddress one or more problems in the prior art.

In a first aspect, the present application provides a method forenabling a user equipment to access a radio network, comprising:determining, by a network equipment, whether a predetermined conditionis satisfied; and if yes, the method further comprises: transmitting, bythe network equipment, information indicating whether a radio network towhich the network equipment belongs is isolated, such that the userequipment performs related operations.

In some embodiments, the predetermined condition is a state change ofthe network equipment, and wherein the state change comprises a changefrom a state of macro network connection to a state of isolated network,a change from one isolated network to another isolated network, or arecovery from the state of isolated network to the state of macronetwork connection; and wherein the transmitting comprises: instructingthe user equipment to carry out a detachment or re-attachment operation.

In some embodiments, the instructing comprises: determining a userequipment which needs to be detached or re-attached, according to aradio context of the user equipment in a radio access network; andtransmitting a detachment request message or a re-attachment requestmessage to the determined user equipment.

In some embodiments, the instructing comprises: receiving a locationupdate request message or a service request message transmitted by theuser equipment; determining whether there is a context of the userequipment in the network equipment; and transmitting a location updaterejection message or a service rejection message to the user equipment,if there is no context of the user equipment, wherein the locationupdate rejection message or the service rejection message, of which arejection reason indicates the detachment or re-attachment.

In some embodiments, the method further comprises: modifying a trackingarea identification (TAI) of a cell as a predetermined TAI, which isdedicated to the isolated network, if the state of the network equipmentchanges from the state of macro network connection to the state ofisolated network or from one isolated network to another isolatednetwork, wherein the location update request message or the servicerequest message is transmitted by the user equipment upon thepredetermined TAI is detected.

In some embodiments, the instructing comprises: releasing the userequipment in a connection state, wherein a releasing reason indicatesthe detachment or the re-attachment.

In some embodiments, the method further comprises: determining,according to a preset subscription information of the user equipmentregarding allowance of access an isolated network, whether it is allowedfor the user equipment to access the isolated network.

In some embodiments, the predetermined condition comprises: anexpiration of a predetermined time, or the network equipment being in astate of isolated network when it is enabled, or a state change of thenetwork equipment, and wherein the state change comprises: a change froma state of macro network connection to a state of isolated network, achange from one isolated network to another isolated network, or arecovery from the state of isolated network to the state of macronetwork connection; and wherein the transmitting comprises: transmittinga cell system information, wherein the cell system information is set asa cell system information dedicated to an isolated radio network, whenthe radio network to which the network equipment currently belongs isisolated.

In some embodiments, the cell system information which is dedicated tothe isolated radio network comprises at least one of: a public landmobile network (PLMN) identification which is dedicated to the isolatedradio network; a tracking area identification (TAI) which is dedicatedto the isolated radio network; a closed subscriber group (CSG)identification which is dedicated to the isolated radio network; anidentification which is dedicated to the isolated radio network; anisolated state indication; information indicating whether or not a userequipment associated with any one of the above identifications will beallowed to access the network; a cell barring indication for preventingsuch a user equipment that has the subscription information indicatingthat it is not allowed to access the network from initiating an accessrequest; an access class barring information of the isolated radionetwork, which indicates the class of a user equipment which is allowedor not to access the isolated radio network; and an indicationinformation indicating whether the user equipment is detached orre-attached.

In some embodiments, the method further comprises: updating the cellsystem information to a cell system information of a macro network or anisolated network to which the network equipment belongs, in response tothe state change of the network equipment.

In some embodiments, the network equipment is a base station or amobility management entity apparatus.

In a second aspect, the present application provides a method for a userequipment accessing to a radio network, comprising: receiving, by theuser equipment, information from a network equipment, wherein thereceived information indicates whether the radio network to which thenetwork equipment belongs is isolated, and the information istransmitted by the network equipment in response to a predeterminedcondition being satisfied; and performing related operations accordingto the received information.

In some embodiments, the predetermined condition is a state change ofnetwork equipment, and wherein the state change comprises: a change froma state of macro network connection to a state of isolated network, achange from one isolated network to another isolated network, or arecovery from the state of isolated network to the state of macronetwork connection; and wherein the receiving comprises: receiving aninstruction of detachment or re-attachment; and the performingcomprises: deleting a context of previously attached Evolved PacketSystem (EPS); or initiating an attachment to the network equipment.

In some embodiments, the receiving comprises any one of: receiving adetachment request message or re-attachment request message; receiving adetachment request message, wherein the detaching is caused due to are-attachment; receiving a location update rejection message or aservice rejection message, of which a rejection reason indicates thedetachment or re-attachment; and receiving a RRC connection releasemessage, of which a releasing reason indicates detachment orre-attachment.

In some embodiments, the performing comprises: determining whether ornot to access the radio network, at least in part based on a presetsubscription information of the user equipment regarding whether it isallowed to access the isolated network, and if yes, initiatingattachment to the network equipment; otherwise, deleting a context ofpreviously attached Evolved Packet System (EPS) or the attachment to thenetwork equipment will not be initiated.

In some embodiments, the predetermined condition comprises: anexpiration of a predetermined time, or the network equipment being in astate of isolated network when it is enabled, or a state change of thenetwork equipment, wherein the state change comprises: a change from astate of macro network connection to a state of isolated network, achange from one isolated network to another isolated network, or arecovery from the state of isolated network to the state of macronetwork connection; the receiving comprises: receiving a cell systeminformation, wherein the cell system information is configured as a cellsystem information dedicated to the isolated radio network, when thenetwork equipment is isolated; and the performing comprises: determiningwhether the context of previously attached evolved packet system (EPS)is deleted or the attachment is initiated, according to the cell systeminformation.

In some embodiments, the cell system information dedicated to theisolated radio network comprises at least one of: a public land mobilenetwork (PLMN) identification dedicated to the isolated radio network; atracking area identification (TAI) dedicated to the isolated radionetwork; a closed subscriber group (CSG) identification dedicated to theisolated radio network; an identification dedicated to the isolatedradio network; an isolated state indication; information indicatingwhether it is allowed to access the user equipment associated with anyone of the above identifications; a cell barring indication forpreventing the user equipment having subscription information which isnot allowed to access from initiating a request for accessing; an accessclass barring information of the isolated radio network indicating classof a user equipment which is allowed or rejected to access the isolatedradio network; and indication information indicating whether the userequipment is detached or re-attached.

In some embodiments, when the received cell system information is thecell system information dedicated to the isolated radio network, theperforming comprises: determining access the radio network, at least inpart based on the cell system information and the preset subscriptioninformation of the user equipment regarding whether it is allowed toaccess the isolated network; and initiating attachment to the networkequipment in response to the access being determined.

In some embodiments, when a plurality of cell system information arereceived, the performing comprises: determining whether the cell and acell in which the user equipment resides previously belong to a sameisolated network, or belong to the macro network, or whether there is aconnection between the network to which the cell belongs and the networkto which the cell in which the user equipment resides previouslybelongs, according to the cell system information; and selectingpreferably the cell belonging to the same isolated network as the cellin which the user equipment resides previously or the cell belonging tothe macro network or the cell having connections with the cell in whichthe user equipment resides previously, during re-selection of cell.

In some embodiments, the performing further comprises: initiatingattachment to the network equipment's of the selected cell, if theselected cell after the cell re-selection and a cell in which the userequipment resides previously do not belong to a same isolated network,or do not belong to the macro network, or there is no connection therebetween.

In a third aspect, the present application provides a network equipmentcomprising a receiver, a transmitter and a processor, wherein theprocessor is configured to determine whether a predetermined conditionis satisfied; and control the transmitter to transmit informationindicating whether a radio network to which the network equipmentbelongs is isolated, if it is determined that the predeterminedcondition is satisfied; and the transmitter is configured to transmitthe information under the control of the processor, and the processor isfurther configured to control the receiver and the transmitter toperform operations associated with a user equipment.

In the fourth aspect, the present application provides a user equipmentcomprising: a transmitter; a receiver configured to receive, from anetwork equipment, information indicating whether a radio network towhich the network equipment belongs is isolated, wherein the informationis transmitted by the network equipment in response to a predeterminedcondition being satisfied; and a processor configured to control thetransmitter to perform related operations according to the information.

With the method for enabling the user equipment to access the radionetwork, the network equipment and the user equipment provided by thepresent application, state information regarding whether the radionetwork to which the network equipment belongs is isolated or not isinformed to UE via the network equipment in different ways, so that theisolated network can provide the users with reliable local bearersupporting service continuity, thereby meeting communicationrequirements with public safety and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, objects and advantages of the present application willbe more apparent with a review of a detailed description of thenon-limiting embodiments set forth below with reference to the attacheddrawings.

FIG. 1 is a system architectural diagram of a System ArchitectureEvolution (SAE);

FIG. 2 illustrates a flowchart 200 of one example of the method forenabling the user equipment to access the radio network provided by thepresent application and implemented at the network equipment's side;

FIG. 3 illustrates a flowchart 300 of one example of the method forenabling the user equipment to access the radio network provided by thepresent application and implemented at the user equipment side;

FIG. 4 illustrates an example of signaling flow transmitted between UEand the network equipment according to an embodiment of the presentapplication;

FIG. 5 illustrates an exemplary implementation of signaling flow betweenUE and the network equipment, for enabling UE to access the radionetwork according to an embodiment of the present application;

FIG. 6 illustrates another exemplary implementation of signaling flowbetween UE and the network equipment, for enabling UE to access theradio network according to an embodiment of the present application;

FIG. 7 illustrates further exemplary implementation of signaling flowbetween UE and the network equipment, for enabling UE to access theradio network according to an embodiment of the present application;

FIG. 8 illustrates an exemplary implementation of signaling flow betweenUE and the network equipment, for enabling UE to access the radionetwork according to an embodiment of the present application;

FIG. 9 illustrates another exemplary implementation of signaling flowbetween UE and the network equipment, for enabling UE to access theradio network according to an embodiment of the present application; and

FIG. 10 is a simplified block diagram of an entity of various exemplaryembodiments adaptable to implement the present application.

DETAILED DESCRIPTION

Hereinafter, the present application will be further explained in detailin connection with the embodiments and the accompanying drawings. Itshould be understood that specific embodiments described herein are onlyintended to explain the relevant invention, rather than to limit theinvention. In addition, it should be noted that only a portionassociated with the present invention is shown in the accompanyingdrawings for ease of description.

Provided that there is no conflict, it should be noted that theembodiments, and features in the embodiments of the present applicationmay be combined. Hereinafter, the present application will be explainedin detail with reference to the accompanying drawings in connectivitywith the embodiments.

Hereinafter, a base station (BS) is an access apparatus for accessing acommunication apparatus to a cellular network and is used to allocatecommunication resources to the communication apparatus. The base stationmay be any one entity of an enhanced Node B (eNB), a Node B, a radioaccess unit, a base station controller, a base transceiver station andetc. The communication apparatus may be any apparatus intended to accessservices via access networks and may be configured to communicatethrough the access networks. For example, the communication apparatusmay comprise, but not limit to, a user equipment (UE), a mobile station(MS), a cellular phone, a smart phone, a computer or a multimedia systemwith communication functions. It should be noted that terms“communication apparatus”, “user equipment” and “user terminal” may beused interchangeably hereinafter.

It also should be noted that, although embodiments are describedhereinafter in a cellular network of LTE/LTE-A type for purposes ofillustration, those skilled in the art can recognize that the disclosedembodiments can also be applied to other types of cellular network.

As mentioned above, although the isolated radio access network togetherwith the local core network can constitute an integral isolated radionetwork, there are many problems as below.

Problem (1): UE is unaware of the base station becoming isolated. Theisolated radio network generally only allows the public safety UE toaccess. The nonpublic safety UE may initiate access aimlessly, therebycausing unnecessary access overhead and affecting the access of thepublic safety UE. For the public safety UE in the coverage of theisolated base station, if the UE has attached to the macro core networkpreviously, the UE could misunderstand that it can continuously obtainservices via that base station, since the UE doesn't know the corenetwork of the isolated network to which the base station belongs doesnot have the UE contexts.

Problem (2): The UE does not know that the base station is recoveredfrom the isolated state. For example, after the backhaul between thebase station and the macro core network is repaired, the base stationcan re-connect to the macro core network. At this time, the base stationmay close or disengage from the core network of the isolated network.For the public safety UE in the coverage of the base station, if the UEhas attached to the core network of the isolated network previously, theUE will misunderstand that it can continuously obtain services via thatbase station, since the UE doesn't know the macro core network to whichthe base station connects does not have the UE context. For thenonpublic safety UE, which tried to attach to the isolated network viathe base station but is rejected previously, may misunderstand that thatbase station still cannot be accessed to.

Problem (3): UE does not know that the base station changes from oneisolated network to another isolated network. For example, a nomadicbase station is disengaged from an isolated network and becomes a newisolated network or joins another isolated network. At this time, thecore network to which the base station connects will change, and theremay be no connection between the core network before state changed andthe core network after state changed. The core network after statechanged does not have the context of UE which has attached to the corenetwork before state changed. Therefore, UE does not know that the corenetwork to which the base station connects has changed and willmisunderstand that it can continuously obtain services via that basestation.

Problem 4: when UE moves under the coverage of isolated network andmoves from cell-1 to cell-2, several circumstances may exist. (1) tcell-1 belongs to the macro network while cell-2 belongs to an isolatednetwork; (2) cell-1 belongs to an isolated network while cell-2 belongsto the macro network; (3) cell-1 belongs to isolated network-1 whilecell-2 belongs to isolated network-2; and (4) both cell-1 and cell-2belong to the same isolated network. For the first three circumstances,there is no interconnection or interworking between the network ofcell-1 and the network of cell-2. If a UE has attached the network ofcell-1, the context of the UE cannot be transmitted to the network ofcell-2. If the UE wants to obtain services via cell-2, it needs tore-attach to the network of cell-2. The four circumstances cannot bedistinguished by UE by now.

Problem 5: there is a plurality of isolated radio network in the radioenvironment, and there are no interconnections or interworking betweenthese isolated radio networks. When UE moves among cells of the isolatednetwork, to avoid a re-attachment, UE can select preferably the cell ofthe isolated network to which UE has attached previously. However, UEcannot distinguish which cell belongs to which isolated networkrespectively.

Problem 6: when there is overlapped coverage between the isolated radioaccess network and the normal radio access network, when selectingcells, UE can select preferably the cell of the normal radio accessnetwork connected with the macro core network. Therefore, UE can accessexternal internet or other applications through the mobile networkwithout re-initiating attachment, thereby protecting service continuity.However, UE does not know which network is isolated radio access networkor which network is the normal radio access network.

Problem 7: there might be not the public safety UE related authorizationinformation in the local core network.

To address one or more problems as described above and to enable UE toknow information regarding whether the network to which the networkequipment belongs is isolated or not, an embodiment of the presentapplication provides a solution for enabling the user equipment toaccess the radio network.

FIG. 2 illustrates a flowchart 200 of one embodiment of the method forenabling a user equipment to access a radio network provided by thepresent application and implemented at the network equipment's side. Theflowchart 200 comprises the following steps 201 and 202.

At step 201, the network equipment determines whether a predeterminedcondition is satisfied.

The predetermined condition may be an expiration of a predeterminedtime, or the network equipment is enabled as in a state of isolatednetwork, or a change of a state of network equipment, wherein the changecomprises a change from a state of macro network connection to a stateof isolated network, a change from one isolated network to anotherisolated network, or a recovery from the state of isolated network tothe state of macro network connection.

At step 202, the network equipment transmits information indicatingwhether a radio network to which the network equipment belongs isisolated, such that the user equipment performs related operations, ifit is determined that the predetermined condition is satisfied.

FIG. 3 illustrates a flowchart 300 of one embodiment of the method forenabling the user equipment to access the radio network provided by thepresent application and implemented at the user equipment's side. Theflowchart 300 comprises the following steps 301 and 302.

At step 301, the user equipment receives, from the network equipment,information indicating whether the network equipment is isolated, whichis transmitted by the network equipment in response to a predeterminedcondition being satisfied.

The predetermined condition is that described at step 201, and thus thedescription thereof is omitted here.

At step 302, the user equipment performs related operations according tothe information.

Different predetermined conditions may correspond to differentindications, respectively. The exemplary implementations for enablingthe user equipment to access the radio network according to the presentapplication will be described hereinafter in connection with specificembodiments.

Embodiment 1

In the embodiment, the predetermined condition is a change of a state ofnetwork equipment, and the details thereof are described in step 201 andare not repeated here. In the embodiment, the step of transmittinginformation indicating whether the radio network to which the networkequipment belongs is isolated may include a step of instructing the userequipment to detach or re-attach, that is, instructing indirectly orimplicitly that the radio network has been isolated. The networkequipment may be a base station, eNB or an MME.

FIG. 4 illustrates an example of signaling flow transmitted between UEand the base station according to the embodiment of the presentapplication. Those skilled in the art can understand that for purposesof illustration and ease of understanding, one or more particulartechnical details are illustrated and described in the followingdescription, but the embodiments of the present application may beimplemented without these features.

As shown in FIG. 4, the following steps 401-402 are included.

At step 401, the network equipment determines that its state changed soas to instruct the user equipment to carry out detachment orre-attachment. The change in state is described in step 201, and thusthe description thereof is omitted here.

In some embodiments, the isolated network generally only allows thepublic safety UE or the UE having subscription information of allowingthe UE to access. Therefore, when the state of the base station has beenchanged, for a UE accessing previously, if the core network to which thebase station connected after state changed does not have the UE context,the base station may release connections of these user equipment's. Inaddition, the nonpublic safety UE accessing previously or the UE havingsubscription information of not allowing the UE to access may beinstructed to detach; and the public safety UE or the UE havingsubscription information of allowing the UE to access may be instructedto re-attach to the isolated network, in order to be served by theisolated network.

At step 402, the user equipment receives instructions of detachment orre-attachment from the network equipment. The user equipment performscorresponding actions, such as detachment, i.e., deleting the context ofpreviously attached EPS, or re-attachment, i.e., initiating attachmentto the network equipment, according to the received instructions.

FIG. 5 illustrates an exemplary implementation of signaling flow betweenUE and a network equipment (such as a base station or an MME to whichthe base station connects) for enabling UE to access the radio networkaccording to an embodiment of the present application.

In the implementation, after it is determined that the state haschanged, the network equipment initiates detachment or re-attachment tothe UE. The change of state is described in step 201, and thus thedescription thereof is not repeated here.

As shown in FIG. 5, the following steps 501 and 502 are included.

At step 501, after the state of the base station changed, the basestation or MME to which the base station connects may transmit a detachrequest message to UE which needs to be detached, thereby instructingthe UE to detach or re-attach.

The change in state is described in step 201, and thus the descriptionthereof is omitted here.

Alternatively, the network equipment may determine the user equipment(UE) which needs to be detached or re-attached, according to the radiocontext of the user equipment (UE) in the radio access network. When aradio context of one UE exists in the base station, it can deduce that,before the state of the base station has changed, the UE has attached tothe core network to which the base station connects before statechanged.

Alternatively, the isolated network may be preconfigured with theinformation of the public safety UE or the subscription information ofthe UE which is allowed to access.

Alternatively, the above request message may also indicate UE that thestate of the base station to which the UE accesses has changed, that is,changing from a state of macro network connection to a state of isolatednetwork, changing from one isolated network to another isolated network,or recovering from the state of isolated network to the state of macronetwork connection. Additionally, the above request message may alsoindicate the identification of the isolated network to which the presentbase station belongs.

At step 502, the UE may perform corresponding actions, such as detach,i.e., deleting the context of EPS, according to the instructionstransmitted by the base station. Alternatively, UE may also returndetach accept message to the base station.

If the base station indicates that its state has changed, UE may knowthe state change of the base station. For example, the network to whichthe base station belongs changes to the state of isolated network fromthe state of macro network connection, changes to another isolatednetwork from one isolated network, or recovers to the state of macronetwork connection from the state of isolated network. At this time, thecore network to which the changed base station connects may not have thecontext of UE, and generally there is no interconnection andinterworking between the core network to which the base station connectsafter state changed and the core network to which the base stationconnects before state changed. If UE still wants to obtain networkservices through the base station, an attachment should be initiated tothe network to which the base station belongs. UE may determine whetherit is allowed to access the network after the base station changed,according to the subscription information of UE. The UE which is notallowed to access does not need to initiate attachment to the isolatednetwork to which the base station belongs, thereby reducing access loadof the isolated network. The nonpublic safety UE does not generallyallow to access the isolated network, and its subscription informationdoes not contain information of allowed to access the isolated network.

If the base station indicates information of the isolated network towhich the base station belongs, UE may determine whether the basestation changes to the isolated state from the state of macro networkconnection, or whether the isolated network to which the base stationbelongs changes. In the case of the state has changed, if UE wants toobtain the network service through the base station, UE needs toinitiate attachment to the core network to which the base stationbelongs. UE may determine whether it is allowed to access the isolatednetwork to which the base station belongs, according to whether thesubscription information comprises the identification of the isolatednetwork to which the base station belongs. The UE which is not allowedto access does not need to initiate attachment to the isolated networkto which the base station belongs, thereby reducing access load of theisolated network. The information of the isolated network may be PLMNidentification, TA identification and CSG identification which arededicated to the isolated network, as well as an identification which isdedicated to the isolated network or UE class (e.g. access class) whichis allowed to access by the isolated network.

FIG. 6 illustrates another exemplary implementation of signaling flowbetween UE and the network equipment for enabling UE to access radionetwork according to an embodiment of the present application. In thisimplementation, when a tracking area update request message or a servicerequest message transmitted by the user equipment (UE) is received afterthe state of network equipment has changed, if there is no context ofthe above user equipment (UE), a tracking area update reject message ora service reject message is transmitted to UE.

As shown in FIG. 6, the following steps 601 to 603 are included.

At step 601, UE transmits the tracking area update request or servicerequest to the network equipment (a base station or an MME to which thebase station connects).

Alternatively, when the network equipment determines that its statechanges to the state of isolated network from the state of macro networkconnection or changes to another isolated network from one isolatednetwork, the network equipment may modify the tracking areaidentification (TAI) of a cell to a preset TAI supported by the networkto which the base station belongs, wherein the preset TAI of the macronetwork is different from TAI of the isolated network, and TAI ofdifferent isolated networks are different too. Therefore, when the stateof the network equipment has changed, the TAI supported by the cell ofthe network equipment is different from that before state changed, andthe UE attached to the network of the base station before state changedmay detect a new TAI, and thus the UE will transmit the tracking areaupdate request message to the corresponding network equipment.

At step 602, if there is no context of UE in the MME to which the basestation connects, the base station or the MME to which the base stationconnects returns the tracking area update reject or service rejectmessage to UE. The reject message may indicate one or more ofre-attachment, there is no UE context, the identification of isolatednetwork, or the base station to which the UE accesses turns into a stateof isolated network.

At step 603, UE performs corresponding actions, such as detach, i.e.,deleting the context of EPS, according to the instructions transmittedby the base station or the MME to which the base station connects.

If the base station or MME to which the base station connects indicatesthe state of isolated network, or if it is the macro network to which UEattached previously through the base station, UE knows no UE contextexists in the core network to which the base station newly connects, andthere are no interconnection and interworking between the core networkand the core network of the macro network. If UE still wants to obtainthe network service through the base station, UE needs to initiateattachment to the core network to which the base station belongs. The UEwhich is not allowed to access the isolated network does not need toinitiate attachment to the isolated network to which the base stationbelongs, thereby reducing access load of the isolated network. The nonpublic safety UE generally does not allowed to access the isolatednetwork, and its subscription information doesn't include theinformation of the access permission of the isolated network is notincluded in the subscription information.

The detail operations in which the base station or MME to which the basestation connects indicates the identification of isolated network towhich it belongs may be referred to the descriptions in step 502, andthus are not repeated here.

FIG. 7 illustrates further exemplary implementation of signaling flowbetween UE and the network equipment, for enabling UE to access radionetwork according to an embodiment of the present application.

In this implementation, when the network equipment detects that itsstate has changed, the network equipment disconnect the UE in connectedmode. The change of state is described in step 201, and thus is notrepeated here.

As shown in FIG. 7, the following steps 701 and 702 are included.

At step 701, the base station detects that its state has changed andtransmits a RRC release message to UE in connected mode, to instruct UEto detach or re-attach, or indicate the base station to which the UEaccesses turns into the state of isolated network, i.e., in a satisfiedcondition of isolated state. Alternatively, an identification of theisolated network to which the current base station belongs may beindicated. The change of state is described in step 201, and thus is notrepeated here.

At step 702, after receiving the instruction, UE performs relatedoperations according to the indication. The operations associated withdetach include deleting the context of original EPS. The operationsassociated with re-attachment include initiating attachment to thenetwork equipment.

Embodiment 2

In this embodiment, the predetermined condition comprises an expirationof the predetermined time, or the network equipment being directlyinitiated as the isolated state, or the state of network equipment beingchanged. The predetermined condition is described in step 201, and thusis not repeated here. In this embodiment, the step of transmittinginformation by the network equipment which indicates whether the networkto which the network equipment belongs is isolated may includebroadcasting cell system information. The network equipment may be abase station.

FIG. 8 illustrates an example of signaling flow between UE and thenetwork equipment according to an embodiment of the present application.As shown in FIG. 8, the following steps 801 and 802 are included.

At step 801, the network equipment detects that the predeterminedcondition is satisfied, i.e., the change of state occurs, or the networkequipment is directly initiated to the isolated state, or thepredetermined time expires, and broadcasts the cell system informationto indicate whether the network to which the network equipment belongsis isolated for performing related operations by the user equipment.

The predetermined condition may be referred to the descriptions in step201, and thus is not repeated here.

In this embodiment, the cell system information dedicated to theisolated radio network may include at least one or more of items asbelow: a Public Land Mobile Network (PLMN) identification dedicated tothe isolated radio network; a Tracking Area Identification (TAI)dedicated to the isolated radio network; a Closed Subscriber Group (CSG)identification dedicated to the isolated radio network; anidentification dedicated to the isolated radio network; an isolatedstate indication; a cell barring indication; an Access Class Barring(ACB) information of the isolated network.

(1) In one implementation, the cell system information dedicated to theisolated radio network may be PLMN dedicated to the isolated radionetwork. PLMN may not allow non public safety UE to access, or not allowUE having subscription information which does not allow PLMN to access.Alternatively, PLMN may allow the public safety UE to access, or allowUE having subscription information which allows PLMN to access.

(2) In another implementation, the cell system information dedicated tothe isolated radio network may be the tracking area (TA) identificationdedicated to the isolated radio network. The TA may not allow of thenonpublic safety UE to access, or not allow the access of the UE whichis restricted by the TA. Alternatively, TA may allow the public safetyUE to access, or allow the access of the UE which is not restricted bythe TA.

(3) In further implementation, the cell system information dedicated tothe isolated radio network may be CSG identification dedicated to theisolated radio network. The CSG may not allow the nonpublic safety UE toaccess, or may not allow the access of the UE which is not a member ofthe CSG. Alternatively, the CSG may allow the public safety UE toaccess, or allow the access of the UE which is a member of the CSG.

(4) In yet another implementation, the cell system information dedicatedto the isolated radio network may be the identification dedicated to theisolated radio network. For all cells in one isolated radio network, asame identification of the isolated radio network may be broadcasted.

(5) In yet another implementation, the cell system information dedicatedto the isolated radio network may be the isolated state indication ofthe radio network. When the indication indicates the state of isolation,it is allowed the access of the UE having the subscription informationwhich allows the UE to access the isolated network, while it is notallowed the access of the UE having the subscription information whichdoes not allow the UE to access the isolated network.

(6) In yet another implementation, the cell system information dedicatedto the isolated radio network may be the cell barring indication whichindicates that it is allowed the access of UE having the subscriptioninformation which allows the UE to access the isolated network, while itis not allowed the access of the UE having the subscription informationwhich does not allow the UE to access the isolated network.

(7) In yet another implementation, the cell system information dedicatedto the isolated radio network may be the information indicating whetherthe user equipment is detached or re-attached.

(8) In yet another implementation, the cell system information dedicatedto the isolated radio network may be the ACB (Access Class Barring)information of the isolated radio network, wherein the ACB informationindicates the classes of the user equipment which is allowed or rejectedto access the isolated radio network. The ACB information implementsrestriction to the UE class of the nonpublic safety UE. The publicsafety UE may be configured with a dedicated access class, so that thenonpublic safety UE is rejected to access the isolated radio network,while the public safety UE is allowed to access the isolated radionetwork.

At step 802, after the change of cell system information or the cellsystem information dedicated to the isolated network is monitored, UEmay perform corresponding actions according to specific circumstance ofthe cell system information.

In some embodiments, according to one or more of the followinginformation: the public land mobile network (PLMN) identificationdedicated to the isolated radio network; the tracking areaidentification (TAI) dedicated to the isolated radio network; the closedsubscriber group (CSG) identification dedicated to the isolated radionetwork; the identification dedicated to the isolated radio network; theisolated state indication; the cell barring indication; and the accessClass Barring (ACB) information of the isolated network, UE maydetermine that the network to which the base station belongs haschanged, such as changing to the state of isolated network from thestate of macro network connection, changing to another isolated networkfrom one isolated network, or recovering to the state of macro networkconnection from the state of isolated network. The cell systeminformation is described in step 802, and thus is not repeated here. Fora UE having the subscription information which allows the UE to accessthe network to which the base station belongs, if the UE wants to obtainthe service of the network, the attachment is needed to be initiated.

(1) When the cell system information dedicated to the isolated radionetwork is the PLMN identification, the TA identification, the CSGidentification or the identification of isolated network, UE maydetermine that the network to which the base station belongs has changedaccording to the above change of cell system information.

(2) When the cell system information dedicated to the isolated radionetwork is in the isolated state, the cell barring indication or theaccess class barring, UE may determine that the base station is in thestate of isolated network, according to the isolated state turning intoisolated or the state of cell barring being true, or the access classbarring only allowing the class which is dedicated to public safety UE.Otherwise, the base station is in the state of macro network connection.

(3) When the cell system information dedicated to the isolated radionetwork is in the isolated state and/or the identifications of (1), UEmay determine that the network to which the base station belongs haschanged, according to the above change of cell system information.

(4) When the cell system information dedicated to the isolated radionetwork is the cell barring indication and/or the identifications of(1), UE may determine that the network to which the base station belongshas changed, according to the above change of cell system information.

(5) When the cell system information dedicated to the isolated radionetwork is the access class barring and/or the identifications of (1),UE may determine that the network to which the base station belongs haschanged, according to the above change of cell system information.

In some embodiments, the rejected PLMN of isolated network will be savedin the PLMN rejection list of UE. When the base station is recovered tothe state of macro network connection, the PLMN is deleted from the PLMNrejection list.

In some embodiments, UE detects whether it is allowed to access theisolated network to which the base station belongs, based on the presetsubscription information. In some implementation, the subscriptioninformation of UE may be information of whether it is allowed to accessthe isolated network, or whether it is allowed to access the dedicatedisolated network, indicating the identification information of theisolated network. In some implementation, the information about whetherit is allowed to access the isolated network may be the PLMNidentification, the TA identification, the CSG identification, the UEaccess class which is allowed by the isolated network, or the cellbarring indication of the isolated network.

In some implementation, the identification information dedicated to theisolated network may be the PLMN identification, the TA identification,the CSG identification or the access class.

In some implementation, the subscription information of isolated networkand the subscription information of non-isolated network are separated.

In some other embodiments, when the area where UE is located in thecoverage of a plurality of network, UE may receive a plurality of cellsystem information. At this time, according to the cell systeminformation, UE may determine firstly whether both the detected cell(s)and the cell previously camped by the UE belong to the same isolatednetwork, or both of them belong to the macro network, or whether thereis a connection between the network to which this detected cell belongsand the network of the cell previously camped by the UE. During there-selection of cell, the cell which belongs to the same isolatednetwork previously camped by the UE or belongs to the same macro networkor which has connections with the of the cell previously camped by theUE is preferably selected.

In some embodiments, if the cell reselected after the re-selectionbelongs to a different isolated network from the cell previously campedby the UE, or the reselected cell and the cell previous camped are notall belongs to the macro network, or the reselected cell has noconnection the network of the cell previously camped by the UE,attachment should be initiated by the UE to the network equipment's ofthe reselected cell.

FIG. 9 illustrates another exemplary implementation of signaling flowbetween UE and the network equipment for enabling UE to access radionetwork according to an embodiment of the present application.

In this implementation, a process of attaching to the isolated networkto which the base station belongs by the user equipment is shown.

As shown in FIG. 9, the following steps 901 and 902 are included.

At step 901, UE requests the isolated base station for establishing aRRC connection. A UE class indication is indicated in the RRC connectionrequest message. The UE is a public safety UE class. For the UE innon-public safety class, the indication is not included in the RRCconnection.

At step 902, the isolated base station rejects directly the RRCconnection request message which does not include the UE classindication and transmits a RRC connection reject message.

With this operation, the connection request of nonpublic safety UE isrejected directly. Especially when accidence occurs, the access capacityof the isolated base station can be avoided to be over occupied by alarge number of connection establishment requests of nonpublic safetyUE, which may cause public safety UE fail to access normally.

It can be seen from the above descriptions of embodiments of the presentapplication, regardless of radio access network entities losing backhaulnetwork connections or the nomadic access network entities, users withpublic safety and the like may be provided with reliable local bearersupport of service continuity. The proposed technical solution may meetcommunication requirements for public safety in the circumstances ofdisasters.

FIG. 10 is a simplified block diagram of an entity 1000 of variousexemplary embodiments adaptable to practice the present application. Theentity 1000 may be configured to be an apparatus at network side, suchas a base station. The entity 1000 may also be configured to anapparatus at user side, such as a user terminal.

As shown in FIG. 10, the entity 1000 comprise a processor 1001, a memory1002 coupled to the processor 1001, and a suitable radio frequency (RF)transmitter/receiver 1004 coupled to the processor 1001. The memory 1002stores programs 1003. The transmitter/receiver 1004 is suitable fortwo-way radio communication. It should be noted that thetransmitter/receiver 1004 has at least one antenna for assistingcommunication, and in practice, the base station or UE may have aplurality of antennas. The entity 1000 may be coupled to one or moreexternal networks or systems, such as internet, via data paths.

The program 1003 may comprise program commands. When the programcommands are executed by associated processor 1001, the entity 1000 mayoperate according to the respective exemplary embodiments of the presentapplication.

The embodiments of the present application can be implemented bycomputer software which could be executed by the processor 1001 of theentity 1000, or by hardware, or by the combination of software andhardware.

The memory 1002 may be any appropriate type of memory suitable for localtechnical environment, and may be achieved by any appropriatedata-storage technology, for example, a memory device and system basedon semiconductor, a magnetic memory device and system, an optical memorydevice and system, a fixed memory and a removable memory, which are onlysome non-restrictive examples. Although only one memory is illustratedin the entity 1000, a plurality of physically independent memory unitsmay be contained by the entity 1000. The processor 1001 may be anyappropriate type of processor suitable for local technical environment,and may comprise one or more of the followings: a general-purposecomputer, a special-purpose computer, a microprocessor, a digital signalprocessor (DSP) and a processor based on multi-core architecture, whichare only some non-restrictive examples.

When the entity 1000 is configured to be apparatus at network side, thatis, the entity 1000 is a network equipment such as a base station, etc.in some embodiments, the processor 1001 is configured to determinewhether the predetermined condition is satisfied, and if it isdetermined that the predetermined condition is satisfied, the processor1001 controls the transmitter to transmit the information indicatingwhether the radio network to which the network equipment belongs isisolated.

The transmitter of transmitter/receiver 1004 is configured to transmitthe above information under control of the above processor.

The processor 1001 is also configured to control the above receiver andtransmitter to perform related operations with the user equipment.

When the entity 1000 is configured to be an apparatus at user side, thatis, the entity 1000 is a user equipment, in some embodiments, thereceiver of transmitter/receiver 1004 is configured to receive, from thenetwork equipment, the information indicating whether the radio networkto which the network equipment belongs is isolated, wherein theinformation is transmitted by the network equipment in response topredetermined conditions being satisfied.

The processor 1001 is configured to control the above the transmitter toperform related operations, according to the above information.

It should be comprehended that, each unit comprised in the entity 1000is configured to implement the exemplary embodiments disclosed in thepresent application. Therefore, the above operations and feathersdescribed by combining FIG. 2 to FIG. 9 are also applicable to theentity 1000 and the units therein, and a detailed description thereofwill be omitted herein.

In addition, there is provided a computer readable storage medium, whichmay be the computer readable storage medium contained in the source basestation, the target base station or the secondary base station in theabove embodiments, or a computer readable storage medium individuallyexists rather than being fitted into any apparatus. There is one or morecomputer programs stored on the computer readable storage medium, andone or more processors run the one or more computer programs to performthe method for a user equipment accessing to a radio network mentionedin the present application.

The above description is only the preferred embodiments of the presentapplication and the description of the principles of applied techniques.It will be appreciated by those skilled in the art that, the scope ofthe claimed solutions as disclosed in the present application are notlimited to those consisted of particular combinations of featuresdescribed above, but should cover other solutions formed by anycombination of features from the foregoing or an equivalent thereofwithout departing from the inventive concepts, for example, a solutionformed by replacing one or more features as discussed in the above withone or more features with similar functions disclosed (but not limitedto) in the present application.

1. A method by a base station in a wireless communication system, themethod comprising: detecting a loss of a backhaul between the basestation and a macro core network; determining to activate an operationof a mode for an isolated network based on the detection; transmittingsystem information including a public land mobile network (PLMN)identity dedicated to the isolated network in case that the mode for theisolated network is in operation based on the determination; andreceiving, from a user equipment (UE), a message for attaching to theisolated network.
 2. The method of claim 1, wherein the systeminformation further includes information associated with a tracking areadedicated to the isolated network.
 3. The method of claim 1, wherein theisolated network is accessed by the UE with a predetermined accessclass.
 4. The method of claim 1, wherein the system information furtherincludes at least one of a closed subscriber group (CSG) identifierdedicated to the isolated network, an identifier dedicated to theisolated network, and information on an access class indicating at leastone access class of the UE which is allowed or rejected to access theisolated network.
 5. The method of claim 1, wherein an access of the UEto the isolated network is determined based on subscription informationindicating whether a PLMN allows the UE to access to the isolatednetwork.
 6. A method by a user equipment (UE) in a wirelesscommunication system, the method comprising: receiving systeminformation transmitted from a base station operating in an isolatednetwork mode, the system information including a public land mobilenetwork (PLMN) identity dedicated to the isolated network; identifyingwhether the UE is capable of accessing the isolated network; andtransmitting, to the base station, a message for attaching to theisolated network using the system information, based on theidentification.
 7. The method of claim 6, wherein the system informationfurther includes information associated with a tracking area dedicatedto the isolated network.
 8. The method of claim 6, wherein the UE with apredetermined access class is capable of attaching to the isolatednetwork.
 9. The method of claim 6, wherein the system informationfurther includes at least one of a closed subscriber group (CSG)identifier dedicated to the isolated network, an identifier dedicated tothe isolated network, and information on an access class indicating atleast one access class of the UE which is allowed or rejected to accessthe isolated network.
 10. The method of claim 6, wherein an access ofthe UE to the isolated network is determined based on subscriptioninformation indicating whether a PLMN allows the UE to access to theisolated network.
 11. A base station in a wireless communication system,the base station comprising: a transceiver; and a controller coupledwith the transceiver and configured to control to: detect a loss of abackhaul between the base station and a macro core network, determine toactivate an operation of a mode for an isolated network based on thedetection, transmit system information including a public land mobilenetwork (PLMN) identity dedicated to the isolated network in case thatthe mode for the isolated network is in operation based on thedetermination, and receive, from a user equipment (UE), a message forattaching to the isolated network.
 12. The base station of claim 11,wherein the system information further includes information associatedwith a tracking area dedicated to the isolated network.
 13. The basestation of claim 11, wherein the isolated network is accessed by the UEwith a predetermined access class.
 14. The base station of claim 11,wherein the system information further includes at least one of a closedsubscriber group (CSG) identifier dedicated to the isolated network, anidentifier dedicated to the isolated network, and information on anaccess class indicating at least one access class of the UE which isallowed or rejected to access the isolated network.
 15. The base stationof claim 11, wherein an access of the UE to the isolated network isdetermined based on subscription information indicating whether a PLMNallows the UE to access to the isolated network.
 16. A user equipment(UE) in a wireless communication system, the UE comprising: atransceiver; and a controller coupled with the transceiver andconfigured to control to: receive system information transmitted from abase station operating in an isolated network mode, the systeminformation including a public land mobile network (PLMN) identitydedicated to the isolated network, identify whether the UE is capable ofaccessing the isolated network, and transmit, to the base station, amessage for attaching to the isolated network using the systeminformation, based on the identification.
 17. The UE of claim 16,wherein the system information further includes information associatedwith a tracking area dedicated to the isolated network.
 18. The UE ofclaim 16, wherein the UE with a predetermined access class is capable ofattaching to the isolated network.
 19. The UE of claim 16, wherein thesystem information further includes at least one of a closed subscribergroup (CSG) identifier dedicated to the isolated network, an identifierdedicated to the isolated network, and information on an access classindicating at least one access class of the UE which is allowed orrejected to access the isolated network.
 20. The UE of claim 16, whereinan access of the UE to the isolated network is determined based onsubscription information indicating whether a PLMN allows the UE toaccess to the isolated network.